This invention relates to a pushing device for sliding fuel rods out of a nuclear reactor fuel assembly.
European Patent Application No. 83 10 7568.4 discloses a so-called dense-packing device which serves to compress, into a packing as dense as possible and preferably into a hexagonal array, fuel rods removed form a reactor fuel assembly and to transfer them into a storage container. To this end it is necessary to slide the fuel rods out of the spacers of the reactor fuel assembly by means of a pushing device and to introduce them into the dense-packing device via guide means, for instance, a guide tube bundle.
After the fuel rods are subjected to a relatively high thermal stress during their operating phase and are also exposed to chemical influences, it may happen that individual fuel rods get jammed in the spacers. In such a case, the pushing device should be switched off altogether above a given pressure in order to avoid major damage. At least the force applied to the jammed fuel rods should be interrupted.
An object of the present invention to provide a pushing device of the above-described type capable of sliding a desired number of fuel rods, in particular, all fuel rods simultaneously, out of the fuel assembly mounting and to introduce them into guidance means for the purpose of placing them in a dense-packing device.
Another object of the present invention is to provide such pushing device in which the force applied to a fuel rod is interrupted or reduced upon a jamming of the fuel rod in its spacer mounting.
Another, more particular, object of the present invention is to provide such a pushing device in which, upon a jamming of one or a small number of fuel rods, many or all of the remaining rods can still be removed.